If this is your first visit, be sure to
check out the FAQ by clicking the
link above. You may have to register
before you can post: click the register link above to proceed. To start viewing messages,
select the forum that you want to visit from the selection below.

Re: ADS-B Out

Last month I installed a Garmin GDL82 in my EX. It works with your existing Mode C transponder as a UAT box transmitting on 978 only. It has been working fine and the installation was simple. It added about 2.5 pounds.

A little over over a year ago I installed a Garmin GTX 335, the Out-only version of Garminís ABS-B transponders, in my Cessna. The 345 that Chip mentions is both Out and In. These are 1090 transponders.

Between the two, the GDL82 is simpler and easier. And in the Cub, panel space is limited, so keeping the little Becker transponder was nice.

I have a GDL 39 3D for In that I move between planes. Having Out makes a big difference in the amount of traffic youíll see pop up on your GPS. And you soon realize that there is more traffic out there than you thought there was.

Re: ADS-B Out

It really depends on what the aircraft is equipped with and what one wants to spend. If its still in the planning stage then there are more options, if its existing then sometimes you have to work with what you have unless you want to spend more on replacing things.

A couple things to remember, for any of it to be truly compliant one needs an approved GPS position source for your ADSB out to be legitimate. ADSB in is completely an option but the out part is what is scrutinized. The GDL 82 is a good solution for an existing mode C unit, but it will not work with a mode S unit.

A GTX 345 or 345R can essentially be stand alone or paired with the G3X, but again must have a valid position source with its own internal GPS receiver or a GPS20A or an approved GPS panel unit, but they are not the only options. The GDL39 or 39R was a good source for ADSB in, I believe it has been replaced with the GDL52. The other thing is antenna, it will need to be a blade type and antenna placement can be an issue.

Re: ADS-B Out

So for a CC with "Garmin G3X Touch Garmin GTX 23 ES Remote Mode S Transponder" what is the simplest ADS-B In/Out solution? Is the GPS20A the only solution for the Mode S?

Jon

Originally Posted by mikesutton

It really depends on what the aircraft is equipped with and what one wants to spend. If its still in the planning stage then there are more options, if its existing then sometimes you have to work with what you have unless you want to spend more on replacing things.

A couple things to remember, for any of it to be truly compliant one needs an approved GPS position source for your ADSB out to be legitimate. ADSB in is completely an option but the out part is what is scrutinized. The GDL 82 is a good solution for an existing mode C unit, but it will not work with a mode S unit.

A GTX 345 or 345R can essentially be stand alone or paired with the G3X, but again must have a valid position source with its own internal GPS receiver or a GPS20A or an approved GPS panel unit, but they are not the only options. The GDL39 or 39R was a good source for ADSB in, I believe it has been replaced with the GDL52. The other thing is antenna, it will need to be a blade type and antenna placement can be an issue.

Re: ADS-B Out

If you have the older GTX23ES and a G3X then as far as I can recall the only solution that was available for that was the GPS20A, which we did use very very briefly until the 335 and 345 came along and there really isn't a direct comparison between the 23ES and the others, especially if you want ADSB in. To use the 20A means you would add the GPS antenna for it and then the appropriate wiring to the G3X system. It doesn't provide primary nav data, its meant to provide the position data to the transponder. 1-866-854-8433, the guys at Garmin back in Olathe can walk one thru it, or the G3X manual which is available on the web shows the various interconnects, one does not have to be a dealer to access it.

Re: ADS-B Out

With the Mode C Becker stub antenna, I originally had it mounted on the aluminum belly access panel. Then I added a belly pod so I moved the stub to the boot cowl, adjacent to the access panel by the gascolator. Ah, but then I installed SB 2 and the new fuel drain goes in the same place. In fact I used the same hole as the antenna had been in for the drain.

The boot cowl is a pretty good place for a transponder antenna but no other location had easy access for installation. And the antenna needs a ground plane. So I decided on the bottom of the leading edge skin. Getting the coax through the nose ribs was easy enough with the landing light removed. And the antenna performance is fine too. I've made a couple Performance Report requests from the FAA and the data they want is getting to the ADS-B tower just fine.

Re: ADS-B Out

Regarding antenna placement, it depends on several things depending on what transponder is being used. I wont go into minute details here nor will I say which is best or worst but I will say that transponders have their own set of criteria for things like db loss thru a given length of cable, antenna ground plane requirements and distance from the antenna to the transponder itself - all of which are almost certainly covered in the install manual for the transponder in question.

If the line loss is too great the effective output signal can be reduced to below desirable levels, and in a general sense its more than the transponder can overcome to transmit the needed signal, it can also make adsb in reception drop off. Some manufacturers also specify a minimum distance from the unit to the antenna to keep rf interference to an acceptable level for the unit in question.

Its a lot different than what one could get by with using the older mode C units, which is why the manufacturers go to all the trouble to print the manuals that so often get ignored or overlooked.